WWI Sentry Post at the Lower Upnor Ordnance Depot

The WWI Sentry Post at the Lower Upnor Ordnance Depot is a Grade II listed structure made of reinforced concrete. It is situated on elevated ground in the south-western part of the site, providing a view over the Lower Upnor Ordnance Depot and the River Medway. This polygonal structure has 11 sides and stands approximately 2.5 meters high, topped with a shallow domed roof.

Access is limited due to vegetation growth, but similar sentry posts typically feature observation apertures on alternate sides. The visible aperture above the small, heavy concrete hatch-doorway, which has steel hinges, has a deep reveal and a very small observation slit. The walls of the sentry post are about 30 centimeters (1 foot) thick, constructed in sections of approximately 60 centimeters (2 feet), similar to other sentry posts at Chattenden/Lodge Hill. The roof is made using a corrugated former. This sentry post was designed as a refuge during combat rather than for permanent occupation, as indicated by the narrowness of the apertures, which suggests it was primarily for observation rather than for firing small arms.